HIGHLAND PARK, Ill. (WLS) -- The suspect in the Highland Park parade shooting that left seven people dead and dozens injured planned the attack for weeks in advance and purchased the rifle legally, authorities said Tuesday.
Robert Crimo III, 21, of Highwood is charged with seven counts of first degree murder, Lake County State's Attorney Eric Rinehart said. They said they anticipate dozens more charges to be filed against him in the coming days.
If convicted, Crimo would be given a mandatory life sentence without the possibility of parole, according to Rinehart.
He is due in bond court Wednesday. Prosecutors will ask for him to be held in custody without bond.
Crimo was arrested in Lake Forest Monday night following an hours-long manhunt.
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Lake County Major Crimes Task Force spokesman Chris Covelli said at a Tuesday morning press conference that Crimo fired more than 70 rounds into the parade.
Covelli said Crimo planned the shooting for weeks and accessed the rooftop of a building using a fire escape ladder. After the shooting, Crimo left his rifle and climbed down to escape while wearing women's clothing to blend in and hide his facial tattoos, Covelli said.
Covelli said Crimo then went to his mother's house and borrowed her 2010 Honda Fit, which he drove to the Madison, Wisconsin, area before returning to Illinois, where he was spotted and arrested.
The weapon was purchased legally, Covelli said. A second rifle was in the car, which investigators believe was also purchased legally. They also found multiple handguns in the Highwood home where Crimo lived with his uncle.
Crimo's parents released a statement through their attorney Tuesday, saying: "We are all mothers and fathers, sisters and brothers, and this is a terrible tragedy for many families, the victims, the paradegoers, the community, and our own. Our hearts, thoughts, and prayers go out to everybody."
"The parents request that all respect their privacy as they try to sort thru this tragedy."
Police said Tuesday Crimo was involved in two prior incidents in Highland Park, the most recent in September 2019 when a family member called police to report he had a knife collection and "was going to kill everyone," authorities said. Police removed knives from Crimo's possession.
Months earlier, in April 2019, someone called police one week after learning Crimo tried to kill himself, police said. Police spoke with Crimo and his parents and learned mental health professionals were handling the situation.
Officials said three months after the second incident, Crimo obtained a firearm owners ID card after being sponsored by his father. Illinois State Police said "there was insufficient basis to establish a clear and present danger and deny the FOID application."
Authorities said the weapon used in the July 4 shooting was purchased after those incidents.
WATCH: Person of interest in parade shooting placed into custody after chase
Highland Park Mayor Nancy Rotering, speaking to CNN Tuesday morning, recalled meeting him as a young boy.
"He was a Cub Scout in my Cub Scout pack. Many years ago, he was just a little boy, a quiet little boy that I knew," she said. "I see this picture, and through the tattoos I see the little boy. It's heartbreaking. I don't know what got him to this point, but let's ask that question of so many people."
A resident of Highwood for the last two years, Crimo lived in the back apartment of an uncle's home, who said his nephew had recently lost his job at a local Panera. He last saw him the day before the shooting.
"Hi, bye. Yeah, he was fine. Everything was normal," Paul Crimo said. "It's hard. It's-I can't even believe it. And, I mean, I feel sorry for all the other families that lost their lives. The six people. My heart goes out to them and I just feel very bad."
Cell phone video captured the sound of gunfire during Highland Park's July Fourth parade. Parade-goers were seen taking cover anywhere they could.
By mid-afternoon Monday, police identified Crimo as a person of interest.
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Crimo's arrest came more than eight hours after the rampage. Bobby Crimo never mentioned political views or talked about weapons or firearms, his uncle said. He has ties to Rockford, De Kalb and Elgin.
Crimo's father, Robert Crimo Jr., had previously run for mayor of Highland Park in 2019, according to three individuals who knew him and public news reporting from the time.
Crimo Jr. was defeated by incumbent Mayor Nancy Rotering, according to ABC7 election results, and only received 28% of the vote.
A local business owner in Highland Park who grew up with Crimo Jr., the father, told ABC News that he was "trying his hardest to help his community" but "probably didn't have that much of a chance."
Residents are still in shock at everything that transpired.
"Thinking about seeing all of my students at the parade, today, and just knowing this is something that they witnessed that they will have to process and go through - it's sickening," witness Lauren Sachs said.
ABC News contributed to this report.